1. Field of the Invention
The present invention relates to a method for waking up a sleeping device, as described in the preamble of claim 1 and the related waking device as described in the preamble of claim 5.
2. Description of Related Art
Such a method and related devices are already known in the art, e.g. from the European Patent Application with reference EP0977112 A2 with title “METHOD AND APPARATUS FOR CONTROLLING POWER OF A COMPUTER SYSTEM ON A LAN (LOCAL AREA NETWORK)” from the inventor Ryu, Chang-Hyun published at Feb. 2, 2000.
Therein, a method for controlling power of a computer system coupled to a communications network, called Local Area Network, using a wake on local area network LAN signal is described. Such a computer system contains a “wake-on-LAN” feature allowing computers that are in a sleeping state, called powered-off state, to wake up, called powered up, at receiving of a wake on LAN signal from a service requesting device on a network interface of the computer system.
However, such a device, when in a sleeping state or going from a sleeping state to a wake up state called the wake up period, is not available to play a role in any networked service because of time-outs, which means that at an incoming request, i.e. an HTTP GET, arriving at such a Personal Computer, even if the PC wakes up, due to time-outs on the underlying TCP and/or TCP layer, the request for service will not be successfully responded to.
Furthermore, such a device in a sleeping state or during the wakeup period is not available because of the volatility and/or unreachability of the IP address because if an application or service (either local or remote) needs to access information that is available on a standby residential network device, there is no means to know the IP address to use or (if the IP address is known), it might be temporarily unreachable. During the period that the device is sleeping or starting up, the device might not have an IP address (released or lease expires) or even when it would have an IP address, the lower layers of the protocol stack will not be able to relate this IP address to a network interface card due to expiring entries in (for example Ethernet) lookup tables.